Automatic hydraulic lifting device for vehicles



Aug.`27, 1940. E. G B. DE MNGHL 2,212,591

AUTOMTICvHYDRAULIC LIFTING DEVICE FOR vVEHIGLES Filed Sept. 13, 1938 3Sheets-Sheet l Aus-27,1940. aan MANGH. 2,212,591

AUTOMATIC HYDRULIC LIFTINGADEVICE FOR VEHICLES Filed sept. 15. 193s asheets-sheet? A118 27, l940- E. G. e. DE MANGHI I l l2,212,591

AUTOMATIC HYDRAULIC LIFTING DEVICE FOR VEHICLES Filed sept. 1s, 193e ssheets-sheet s Patented ug'. 27, 1940 PATENT OFFICE' AUTOMATIC HYDRAULICIJITING DEVICE FOR VEHICLES aida emana Bei-gom as Menem Buenos Aires,Argentina Application September 13, 1938, Serial No. 229,778

2 Claims. (Cl. 25d-86) 'Ihis 4invention relates to an automatichydraulic lifting device for automotive vehicles in general.

Particularly, the lifting device subject of the present invention ischaracterized essentially in that it provides two hydraulic drivingelements constituted by a plurality of chambers within each of whichcoaxially act two pistons constituting the drive transmission meanscorresponding to the liftingu cycle; said means having an articulatedconnection between the ends of the vehicle axle and a plurality ofbearing shoes. Each chamber has two shoes joined together, in pairs, bya bar acting as a means for maintaining the proper separation of theshoes, Said bars are joined longitudinally to the lower portion of thechambers by resilient anchoring means projecting from the chambers andserving to avoid the sudden lowering of the shoes when in inoperativeposition.

.A feature of the present invention resides in the provision for eachchamber of tubular alternative intercommunication means between ahydraulic compressor pump and a uid supply tank communicating with theatmosphere, intercommunication being provided between said pump andsupply tank by means of a tubular branch controlled by a check valve.The tubular means intercommunicating the chambers and pump, constitutethe high pressure conduits, while the tubular means intercommunicatingthe chambers andthe supply tank constitute the low pressure conduits.The high pressure conduits project from the central portion of eachchamber, while the low pressure conduits project from an intermediatebranch coupled to both ends of the respective chamber, land since twopistons act coaxially in each chamber, the latter is thus divided intothree compartments, viz; a central high pressure compartment and twolateral low pressure compartments, said division being determineddirectly by the pistons and the variable cubic capacity depending on thestroke of the pistons.

A further feature of the invention resides in the a interpolation, inthe high and low pressure conduits, and in the group thereof providingthe intercommunication of the chambers, for example the chambercorresponding to the front axle of the vehicle with the compressor pumpandfiuid supply tank, of two two-way valvular means for controlling thecirculation of fluid, one of said v valvular means constituting acut-off valve conmeans constitutes a reversing valve to control thepassage of fluid to either chamber in the low pressure cycle. Thesevalves are hand actuated from the drivers cabin.

A further feature oi the invention resides in the provision ofcommunicating means between the high pressure conduits and the lowpressure conduits, said communicating means consisting of intermediarybranches interpolated between' the reversing valve and said conduits.

.This communication is complementary between Athe high and low pressureconduits and is intended to establish, in alternate cycles, the feed ofthe high pressure chambers, whether through the central portion of saidchambers, corresponding to the lifting cycle, or through the endportions corresponding to the` vehicle lowering cycle.

A still further feature of the invention resides in the provision of anelectromotive element for driving the pressure pump, said element beingactuated directly by the vehicle battery. The starting or shutting oilof said element takes place automatically by the synchronization thereofwith a circuit breaker acting in a chamber branched to the high pressureconduit, said circuit breaker being constituted by a stem which projectsfrom a piston acting in the chamber and which is counteracted upon by anexpansion spring having its tension graduated at a pressure slightlysmaller than that required to establish the operating cycle of thechambers. The said circuit breaker also constitutes a current deectingelement, since it automatically and alternately establishes the closingor opening of the elect-ric circuit between the electromotive agent andan electric lamp located on the vehicle panel or elsewhere within thedriver's sight, and serving toindicate the termination of both thelifting andthe lowering operative cycles.

In order that the invention may be more clearly understood and readilycarried into practice, same has been illustrated by way of example andin a preferred embodiment in the accompanying drawings, wherein:

Figure l is a side elevation and partly sectional view of a chamberconstituting the hydraulic driving means with the several elementsforming same.

Figure 2 is a plan view of the assembly shown in Figurel, showing themanner in which same is coupled to the corresponding vehicle axle, inthe present case and merely for illustrative purposes, the front axle.

Figure' 3 is a plan view of the valvular means u controlling thecirculation of oil between the pump and tank to the chambers and thereturn thereof to the tank.

Figure 4 is an elevation and sectional view taken on the line 4-4 ofFigure 3.

Figure 5 is a schematic view of the electric control of the operation ofthe device.

Figure 6 is a general schematic view of the device, showing thefunctional relation between the parts thereof.

The same reference characters indicate like or equivalent parts orelements throughout the different gures.

The subject of the present invention comprises two hydraulicdrivingfchambers, one for each axle of the vehicle, although forillustrative purposes only that corresponding to the front axle has beenshown in the drawings. y Said cham'- bers comprise a cylindrical tubularcasing I, as shown in Figure 1, within which are coaxially located twopistons 2. The piston rods 3 project outside the chambers throughsuitable packing glands 4, and are connected to both ends of thecorresponding axle, in the case shown the front axle 5, and the shoes 6.The connection .between the rods, axle and shoes comprises two end setsof connecting rods 1 and 8. The connecting rods 1 are articulatedbetween one end of a cross-head 9 xed to the rear end of the rods 3 andthe central portion ofa suitable supporting clamp II), xed to either endof the axle 5, while the connecting rods 8 are articulated to theopposite end of the cross-heads 9 and the upper end of the shoes 6.Shoes 6 are provided with shoulders II which together with projections|2 formed at one end of the clamps IIJ constitute safety stops forkeeping the chamber stabilized during the .vehicle lifting cycle.. Asonly one chamber is shown in the drawings, i. e. that corresponding tothe front axle, forl the sake of simplicity the details of the devicewill also be explained based on said chamber.

Both shoes 6 are connected to each other by means of a bar I3, servingto keep them permanently spaced apart. In turn, said bar I3 is placed infront of anchoring elements constituted by springs I4 of fork-shapedprole and projecting from the bottom of the chamber I, the bar I3 beingheld within said springs when the device is in inoperative position orfolded against the axle, thus preventing any eventual fall thereof incase there is a lack of hydraulic pressure in the chamber ends.

As shown in Figure 6, the chamber has connected thereto two tubularconduits, a high pressure conduit I6, connected to the center of thechamber, and a low pressure conduit I1 connected to both ends of thechamber through an intermediary branch I8 connected to both ends of thechamber. The coupling of the conduit I 5 to the central portion of thechamber, and of the conduit I1 to the branch I8, is effected byinterpolating flexible sleeves I9, and 20, respectively. The elasticityof these sleeves facilitates the displacement of the chamber in theinitial lifting and lowering cycle thereof, respectively. l

The high pressure conduit I5 is connected to a compressor pump 2|, asshown in Fig. 6, while the low pressure conduit is connected with theoil feed tank 22 communicating with the atmosphere by means of anorifice 23. Both the pump 2| and the tank 22 are intercommunicated bymeans of abranch 24 carrying a common check valve 25, the latter servingto prevent the: loss,

of pressure. The check valve 25 is aided by i similar valve 26, arrangedat the mouth of the pump communicating with the conduit I8. The pump 2|is provided with a corresponding plunger 21 which by means of its rod 28is connected to the electromotive element actuating the same in themanner hereinafter described.

Interpolated in the high and low pressure conduits of the chamber aretwo suitably spaced valve structures 29 and 30, of the two-way type.Valve structure 29 includes a valve which controls the circulation offluid between one chamber and the other in the high pressure cycle,while valve structure 30 includes a valve also controlling thecirculation of fluid between both chambers, but in the low pressurecycle. These valves are schematically illustrated in Figure 6, whichalso shows two auxiliary conduits, viz; a high pressure conduit 3| and alow pressure conduit 32, which extend to the chamber provided on therear axle.

Y The high and low pressure conduits IB and I1 intercommunicate by meansof intermediary branches 33 and 34, connected to the valves 2l.Communication between both conduits I8 and |'I is secured by means ofthe branch 33 and a tubular extension 35 connected to the cut-oi! valveand the conduit I5, while communication between I1 and I6, viz; in theopposite direction, is secured by means of the branch 34 and a `tubularextension 36, similar to the extension 35. This arrangement serves toestablish the feed of the high pressure chambers in both lifting andlowering operating cycles, in an alternate manner.

Both valve structures 29 and 30 include two valves which are actuatedfrom the front part of a panel 31, as shown in Figures 3 and 4, throughsuitable knobs 38 and 39 connected to the respective valve stems. Theseknobs are provided with position indicating arrows 40 and 4|, whichextend through the projecting stem of the corresponding male part of thevalve structures, as shown in Figure 4, for the knob 38, by means of agroove 42 having a transverse pin 43. The stems of the respective knobsare provided with a stop 44 fitting in suitable perforations made in thepanel 31, for the purpose of anchoring the knobs in the positioncorresponding to the pre-established cycle of the device.

The stem of the valves 29 has connected thereto a. rotary positiveelectric contact 45 and a rotary negative electric contact 46,rotatingvin conjunction with the rotation given to the stem through theknob 38. These contacts act alternatively on fixed contacts 41 and 48(Figures 3, 4 and 5). Contacts 41 close the circuit of the motor 4l,while contacts 48 close the circuit with the lamp 50 provided in thepanel 31 and indicates the final vehicle lifting and lowering cycles.

'I'he motor 49 is connected to the battery II (Figures 5 and 6) throughelectric conductors 52 and 53, which are series connected byintermediary shuntings connected to each other, between contacts 45, 46,41, 48, to plates 54 and 55. Plate 54 is in the circuit between thebattery and motor, while plate 55 is in the circuit between the batteryand lamp. The metallic terminals 56 and 51 cooperate therewith foropening and closing the respective circuits. Ihe cores of said terminals56 and 51 are connected, by means of a clamp 58 made of insulatingmaterial, to the circuit breaker 59 operated by a compressor chamber 6I,said circuit-breaker projecting from a piston 60. Compressor chamber 6|communicates with the high pressure conduit I6 through an intermediarytubular branchv62. The piston 60 is acted upon by a spring 63, bearingagainst the rear portion of the chamber and having the tension thereofgraduated at a pressure slightly smaller than that required to establishthe functional cycle of the device.

The stroke of the pistons in the chamber I in either direction islimited, for the high pressure cycle corresponding to the lifting of thevehicle, by stops 64 arranged at opposite ends of the chamber, and forthe low pressure cycle corresponding to the lowering ,of the vehicle, bymeans of suitable ribs 65 provided on the confronting faces of thepistons 2. The purpose of the elements 64 and 65 is to provide arelative space between the rear .faces of the pistonsand the ends of thechambers, and between the opposing faces of the pistons when the deviceis in inoperative position, in order to enable the free circulation offluid during the different operating stages of the device.

The operation of the device is as follows: The circuit between thebattery and motor is closed by connecting the rotary contact's 45, 46with contacts 41, thus starting the operation of the pump 2| connectedto the motor throughits rod 28 in any known manner, and startingtherefore the circulation of iiuid through the high pressure conduit I6to the central portion of the chamber I. During this rst stage thecircuit breaker 59 is in circuit with the motor and maintains thecircuit with the lamp apen. Upon the pistons 2 reaching the limit oftheir stroke and engaging vthe stops 64, the iiuid concentrated withinthe chamber due to the continuous operation of the motor reaches itsmaximum pressure, at which time it is communicated with the chamber 6I,striking the `rod 60 and causing the displacement of the circuit breaker59 in opposite' direction to the pressure of spring 63 until it engagesa stop 66 fixed toa support 61 (Figure 6) at which time the terminal 51contacts the plate 55, thereby closing the circuit with the lamp 50 andopening the circuit with the motor, indicating to the driver thetermination of the vehicle lifting cycle. At this time the driverrotates the knob 38 of the reversing valve until the rotary contactsremain separated from. the xed contacts, which he will control throughan indication on the vehicle panel by the arrow 40, thereby blocking allhydraulic communications and leaving the device at a maximum pressuresufcient to maintain the vehicle in a lifted position, without danger ofsudden downward displacements.

To lower the vehicle, once the operations which caused the liftingthereof have been carried out, the driver again actuates the knob of thereversing valve and turns same towards a pre-establishedguide indicationon the panel indicating the communication of the valve Ways,intercommunicating the high pressure conduit I6 with the low pressureconduit I1 by 35, 36, through branches 34 and 33,V thus causing the freecircu-` lation of fluid back to the tank 22, lowering the pressure inthe chamber between the pistons 2 to its lowest limit, equivalent to oneatmosphere. Due to the communication established between the highpressure and low pressure conduits, through the branches 34 and 35, thecircuit breaker simultaneously starts moving backwards, through theaction of spring 63, upon the pressure in chamber 6I being reduced dueto the uid therein escaping through the branch 62. This 1j causes thecircuit breaker to again close the circuit with the motor when theterminal 56 engages plate 54, and the backward motion of the circuitbreaker causes the opening of the circuit with lamp 50. 'I'his re-startsthe motor 49 which again drives the pump 2I the latter sending uid at ahigh pressure to the end portions of the chamber, thus causing theadvance of the pistons 2 towards the central portion of the chamber,thereby starting the lowering of the vehicle as a result of the foldingof the connecting rods 1 and 8. The device closes gradually and upon thepistons reaching their final position determined by the stops 65, thepressure will be raised to the maximum, at which time the circuitbreaker again moves backwardly to establish the opening of the circuitof the 'motor and the closing of the circuit of thelamp 50 therebylighting the same. The device thus remains with chamber 6 I at a,maximum pressure commensurate with that in the end portions of thechamber, and the device is shut-on. The knob 38 of the reversing valve29 is again actuated so as to separate the rotary contacts from thefixed contacts, which causes the opening of the circuit with the lamp,

while the valve interrupts all conduits, xing the device at the maximumpressure and interrupting all electric circuits, stabilizing the closedposition of the device with the aid of the bar I3 engaged'in the groovesI4.

The above description was made with reference to the chambercorresponding to the front axle 5 duit I1, thereby cutting off thecommunication of the rear chamber with pump 2|, tank 22 and the otheroperating and control elements.

What is claimed is:

1. An automatic hydraulic lifting device for vehicles comprising achamber, a pair of pistons acting coaxially within said chamber, apiston rod fixed to each piston projecting outside of said chamber, across head fixed to the end of said I piston rod projecting outside ofsaid chamber, a

shoe for each piston rod, connecting rods connecting each cross head tosaid shoe and to the axle of the vehicle, means for supplying fluidunder pressure, means for supplying uid to said means for supplyingiiuid under pressure, high pressure and low pressure conduits connectingsaid chamber with said means for supplying iiuid under pressure, anelectromotive driving agent for driving said means for supplying iiuidunder pressure, a source of electric current supplying a circuitconnecting saidI electromotive driving agent with said .source ofsupply, hydraulic automatic means located in said circuit operated bythe pressure in said conduits controlling said circuit and valve meansin said conduits controlling communication between said chamber, saidmeans for supplying uid under pressure and said fluid supply means. l

2. An automatic hydraulic lifting device for vehicles comprising achamber, a pair of pistons acting coaxially within said chamber, apiston rod fixed to each piston projecting outside of said chamber,across head fixed to the end of said piston rod projecting outside ofsaid chamber, a shoe for each piston rod, connecting rods connectingeach cross head to said shoe and to u the axle of the vehicle, means forsupplying fluid under pressure, means for supplying fluid to said meansfor supplying fluid under pressure, ,high pressure and low pressureconduits connecting said chamber with said means for supplying uid underpressure, a bar connecting the shoes at each end of said chamber,resilient locking means for said bar on said chamber, an electromotivedriving agent for driving said means for supply- 10- l ing uid underpressure, a source of electric cur-

